The present invention relates to an apparatus for treating a supracondylar fracture of the femur, and one or more methods of treating such fractures.
One injury which may occur in humans is the fracture of the femur. Most commonly, femur fractures are associated with the proximal end of the femur. These types of fractures often result in a fracture of the femoral head from the remaining portion of the femur (known as a xe2x80x9cfemoral neck fracturexe2x80x9d) or a fracture between the neck and shaft (known as an xe2x80x9cinter-trochanteric fracturexe2x80x9d).
An injury which occurs less often, but is occurring with increasing frequency, is a fracture of the distal end of the femur. As is known, a pair of condyles are located at the distal end of the femur. Distal femur fractures may be classified into a variety of types with reference to the condyles. In one class, the fracture is between the shaft of the femur and the condyles of the femur (known as a xe2x80x9csupracondylarxe2x80x9d fracture). In another class of fractures, one or both condyles are fractured from the femur (known as a xe2x80x9ccondylarxe2x80x9d or xe2x80x9cintercondylarxe2x80x9d fracture). In yet another class of fractures there are multiple fractures, through the supracondylar and intercondylar areas of the femur.
A variety of treatments have evolved for fractures of the distal femur. One common method of treatment is illustrated in FIG. 1A. Illustrated in FIG. 1A is a fracture of the first type, i.e. a fracture of the femur proximal to the condyles with the condyles remaining intact. In accordance with one method of treatment, an exterior plate A is positioned along the exterior of the femur. As illustrated, the plate A has a number of passages there through. Screws B are passed through the plate A into the femur both in the region of the condyles and an area proximal thereto. In accordance with this form of treatment, the plate is used to secure the fractured condyles to the femur.
Other forms of the plate described above are known. For example, the plate may have an angled blade in the form of a xe2x80x9cUxe2x80x9d-shaped extension (see FIG. 1B), or an outwardly extending screw (see FIG. 1C). This angled blade or screw may be directed into the condyles, and then the other end of the plate affixed to the femur with screws.
The devices illustrated in FIGS. 1A, 1B and 1C (often termed xe2x80x9ccondylar platesxe2x80x9d) have a number of disadvantages. One significant problem is that the portion of the femur distal to the fracture, i.e. the portion including the condyles, may rotate with respect to the device. When the condyles are placed in a position of stress, that portion of the femur rotates both with respect to the device and the remainder of the femur. This prevents healing of the fracture or healing in an unnatural or non-anatomically correct position.
A similar problem exists in the arrangement in FIG. 1C in that the entire screw which engages the condyles may rotate relative to the plate. Thus, even if the condyles do not rotate relative to the screw, that portion of the femur may still rotate or move relative to the remainder via rotation of the screw through the plate.
Another problem is that fixation is often made difficult when the femur is osteoporotic. In the example illustrated in FIGS. 1A, 1B and 1C, osteoporotic bone may not permit secure engagement of the screws or blade.
Yet another problem with fixation devices applied to the surface of the femur is that the plate must endure significant cantilever moments that may cause the plate to break or screws to pull out of the bone. These methods therefore require that the leg be immobilized and no weight borne upon the leg until the fracture has healed. For example, with reference to the prior art method and device illustrated in FIGS. 1A, 1B and 1C, the connection of the plate A and the plate itself is generally insufficient to adequately fix the fracture to permit the femur to bear weight. In fact, the plate and screws generally can not tolerate any significant load bearing at all. This again results in stresses which increase healing time or prevent healing, at least without other measures such as external bracing, immobilization or the like.
An improved method and apparatus for treating distal femur fracture is desired.
The present invention comprises a method of treating a fracture of the distal femur and one or more apparatus for use in a method of treating a fracture of the distal femur.
In one embodiment, the invention comprises an apparatus including an intramedullary nail and a blade. The intramedullary nail is a generally elongate member having a proximal end (nearest to the condyles of the femur) and a distal end. Preferably, the proximal end of the nail is angled at approximately 10 degrees (in the sagittal plane when inserted in the femur) relative to the remainder of the nail to facilitate insertion. One or more locking member accepting passages are provided through the distal end of the intramedullary nail.
A blade passage extends through the proximal end of the intramedullary nail. The blade passage preferably extends through the intramedullary nail at an angle of about 84-96 degrees (i.e. generally perpendicular) to an axis through that portion of the nail.
The blade also has a proximal end and a distal end. At least one of the ends has a shape which is adapted to engage a portion of a femur in a manner resisting rotation of the femur with respect to the blade. In one embodiment, the proximal and distal ends of the blade include at least two generally planar surfaces which intersect at an angle.
In one embodiment, an apparatus is arranged so that the blade may be fixed from moving with respect to the intramedullary nail. Fixation may be rotational and/or axial/translational. In one embodiment, the shape of the blade and the shape of the blade passage are configured so that at least one surface of the blade interacts with at least one surface of the intramedullary nail defining the blade passage to resist or prevent rotation of the blade with respect to the nail. In one embodiment, the blade passage is generally rectangular in shape and the blade is xe2x80x9cIxe2x80x9d shaped and sized to fit tightly within the blade passage.
In one embodiment, a locking member is provided for locking the blade to the intramedullary nail to resist or prevent axial movement of the blade with respect to the intramedullary nail. In one embodiment, the intramedullary nail includes a passage extending from a proximal tip thereof through the nail to the blade passage. A locking member, such as a screw, may be threaded into the passage into engagement with the blade, locking the blade to the intramedullary nail.
One or more embodiments of the invention comprise a method of treating a fracture of the distal femur. One method includes the step of exposing the distal end of said femur and then extending an intramedullary nail into the medullary space of the femur from the distal end of the femur. Preferably, the intramedullary nail comprises an elongate member having a proximal end and a distal end. The intramedullary nail is extended into the femur until the proximal end of the nail is located near the distal end of the femur. Preferably, the intramedullary nail includes at least one locking member accepting passage located at the distal end thereof.
The method also includes the step of positioning at least one blade member in a portion of the distal end of the femur which is distal to a fracture of the femur. Preferably, the at least one blade member is positioned generally transverse to the intramedullary nail.
The at least one blade member is fixed to the intramedullary nail to generally prevent movement of the at least one blade member with respect to the intramedullary nail. At least one locking member is extended into the femur and the locking member accepting passage located at the distal end of the intramedullary nail.
In one embodiment, the step of fixing the blade to the intramedullary nail comprises mating corresponding portions of the blade and blade passage which are adapted to interfere and generally prevent rotation of the blade with respect to the passage. In another embodiment, the step of fixing includes extending a screw into a passage extending inwardly from the proximal end of the intramedullary nail to the blade passage. The screw is engaged with the blade, fixing the blade from axial and rotational movement with respect to the intramedullary nail.
In another embodiment of the invention, the apparatus includes at least two blades. The blades and passage through the intramedullary nail are shaped and size such that a single blade positioned in the passage may freely move, including rotate, in the passage. However, the passage and blades are configured such that when both blades are positioned in the passage, movement of the blades, including rotation thereof relative to the intramedullary nail, is resisted. In one embodiment, the passage through the intramedullary nail is generally oval in shape, while each blade is xe2x80x9cIxe2x80x9d, xe2x80x9cXxe2x80x9d or xe2x80x9c+xe2x80x9d shaped in cross-section.
In accordance with the apparatus and method, an intramedullary nail provides axial support along the length of the femur, including opposing fractured portions thereof. In addition, a blade member provides secure fixation of a fractured portion of the femur relative to the remainder of the femur by engagement with the intramedullary nail. The blade is adapted to engage the fractured portion of the femur and the intramedullary nail in a manner resisting rotation. The blade is also fixed axially with respect to the intramedullary nail. In this manner, movement of the fractured portion of the femur relative to the remainder of the femur in any plane or rotation around any axis is minimized, and healing time is improved.
The apparatus and method of the invention provide a femur fracture treatment which permits use of the leg soon after treatment. The apparatus is configured to withstand high loads and fix the fractured portion of the femur. In the region of the blade passage, the intramedullary nail is preferably enlarged, providing high strength and stiffness.
An additional aspect of the invention comprises a blade guide and a method of using the blade guide to treat a femur fracture using the nail and blade(s) of the invention. In one embodiment, the blade guide has a first, generally planar portion for connection to the proximal end of a nail. The blade guide has a second portion having at least one passage there through. When the blade guide is connected to an intramedullary nail located in the distal end of a femur, the second portion of the blade guide is located at the medial or lateral side of the distal femur. The passage in the second portion of the blade guide aligns with the blade passage through the intramedullary nail.
In use, the blade guide is connected to the proximal end of an intramedullary nail which is then placed, or already placed, in a femur. In one embodiment, the first portion of the blade guide is connected to the nail with a screw. Because of the generally planar, thin nature of the first portion of the blade guide, the knee may be extended after connection of the blade guide.
A passage is then formed in the femur. The passage is formed using the passage through the blade guide which is aligned with the blade passage in the nail. The passage in the femur may be formed by drilling, punching or the like. Thereafter, one or more blades may be placed into the femur and into engagement with the intramedullary nail.
Further objects, features, and advantages of the present invention over the prior art will become apparent from the detailed description of the drawings which follows, when considered with the attached figures.